Instrument for measuring angles.



No. 746,513. PATENTED DEC. 8, 1903.

F. E. HUTUHINS. INSTRUMENT FOR MEASURING ANGLES.

APPLIGATION FILED NOV. 5, 1902.

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F; E. HUTGHINS. INSTRUMENT FOR MEASURING ANGLES.

APPLICATION FILED NOV. 5. 1902.

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Patented December 8, 1903.

PATENT OFFICE.

FRANCIS EDWINITUTOHINS, OF WARREN, OHIO.

INSTRUMENT FOR MEASURING ANGLES.-

SPECIFICATION forming part of Letters Patent No. 746,513, dated December8, 1903.

Application filed November 5, 1902. Serial No. 180,202. (No model.)

in the art to which it appertains to make and,

use the invcntion,.reference being had tothe accompanying drawings, andto letters and figures of reference marked thereon, which form apart ofthis specification.

Figure l is a side elevation showing th invention. Fig. 2 is a top viewWithout the telescope. Fig. 3 is a front view without the telescope.Fig. 4 is a perspective view of the tangent minute-screw and itsconnections. Figs. 5, 6, and 7 are views of details.

My invention or device is designed to provide for the accuratemeasurement of angles.

It is here described chiefly in its application to the ordinary transitinstrument, although upon the same principle it may be applied to thetheodolite or to other instruments for measuring angles. Applied to thetransit it consists of the rim a, reinforcing the upper circular plate2, carrying the telescope, com-" pass-box, and level to suchcircumference that three hundred and sixty equidistant threads or teethwith the pitch that may be selected will exactly compass it. Theperiphery of this rim is grooved and cut with three hundred and sixtythreads or teeth representing degrees, with the pitch stated laterherein.

The minutes-screw b tangent to the rim a is supported by the uprights30f the frame a. The middle portion a of this minutes-screw is cut Withthreads or teeth corresponding with and serving to engage the threads orteeth in the rim aforesaid, so as to form a screw-gear for rotating theupper circular plate by turning the minutes-screw; The pitch of thethreads in both pieces is such that one revolution ofthe minutes-screwwill movethe upper circular plate just one degree. The frame 0 consistsof a bar 5, (in this case horizontal,) havingalateral projection ti nearthe'rniddle for attachment to the clamp or if the instrument has noclamp then to the lower circular plate or to some part of theinstrumentthat can be fixed while the upper circular plate rotates,there being at each end of the bar an upright 3, through which theminutes-screw passes, the whole forming the support and bearings for theminutes-screw. Thisattachment of the frame to the clamp or other portionof the instrument is adjustable, so as to permit a slight movementof theframe a from andtoward the center, so as to engage and disengage thethreads of the screw-gear aforesaid. This movement is accomplished by aneccentric 7, moving in a slot at the place of attachment and having astem and head for manipulation, the arrangement being such that aquarter-revolution of the cocentric will move the frame so as to engageor disengage the threads of the screw-gear aforesaid. Near the uprightat one end this minutes-screw passes through a vertical dial 8, calledthe minutes-dial, and is so adjusted that the minutes-screw may berotated while the dial remains stationary, or both may be moved togetherand will so move together when the minutes-screw turns, unless the dialis fastened, as by the dial-screw mentioned later. This dial 8 isgraduated by lines on its face at the edge into sixty equal parts forminutes. These lines are numbered by fives from 1'to 60. A stationaryindex or pointer is arranged close to the edge of the face of the dialin such wise that as it revolves its lines and figures of graduationwill move directly past the point of the index. The upright abovereferred to near the dial is usually designed to serve as thisstationary index or pointer in this way: The upright is extended so asto pass up to theedgc of the dial, then across its edge and downward,being brought to a point a short distance down the face of the dial.Past the point of this index the lines and figures revolve as the dialturns. Through that portion of this upright which crosses the edge ofthe dial the dial-screw fpasses into the groove 9 on the edge of thedial. Across the edge ofthe minutes-dial (or of a shallow casingcontaining it) iscut this small groove 9,which is designed to coincidewith the zero-mark, or 60, on the dial, and into this groove the pointedend of the dial-screwf passes, thus fastening the dial with the index at60, while the minutes-screw may revolve, the whole being so arranged asto fasten the dial where the index points to zero, or 60. At the otherend, and outside of that upright, this .min-. utes-screw has a milledhead for manipulation. This completes the minutes device, in which it isapparent that the minutes-screw will serve also every purpose of thetangentscrew in the ordinary transit, besides measuring and indicatingcorrectly the micrometer movement. Toward its head the minlites-screw baforesaid passes through the center of a sector d, through the hub ofwhich a set-screw h (herein called the sector-screw) passes to andagainst the shaft of the minutes-screw and when tightened serves to fixthe sector to the minutes-screw and when loosened permits theminutes-screw to turn while the sector remains stationary. The peripheryof this sector is cut into threads or teeth corresponding with andserving to engage those on the seconds-screw mentioned later herein.

Either mounted upon or forming part of the frame 0 aforesaid is anotherframe 70, consisting of a bar Z, (in this case vertical,) having anoffset p (in this case horizontal) at each end, through which theseconds-screw 8 passes, the whole forming a support and bearings for theseconds-screws. The seconds-screw s, which passes through the offsets ofthe frame It and directly in front of and tangent to and in contact withthe periphery of the sector d. The middle portion of this seconds-screwis cut in threads or teeth to correspond with and to always engage thoseon the periphery of the sector, thus forming a screw-gear for thepartial rotation of the minutes-screw by turning this seconds-screw. Thethreads of this secondsscrew and those of the sector and the radius ofthe sector are such that one revolution of the seconds-screw will turnthe minutesscrew just one-sixtieth of a revolution, or one minute. Atthe lower end this secondsscrewis fastened through the center of a dialt, which is graduated into sixty equal parts for seconds and numberedlike the minutesdial first described and which as the seconds-screw isturned revolves its lines and figures past a stationary index or pointerz to indicate the movement in seconds. At the other end this screw has amilled head for manipulation;

When the clamp or other part on which the frame C is mounted is fastenedand the threads of the minutes-screw and of the rim are engaged, it isapparent that the upper circular plate cannot be turned except byturning the minutes-screw and that when the sector-screw is alsotightened neither that plate nor the minutes-screw can be turned exceptby turning the seconds-screw. Now when in this situation the firstscrewgear is disengaged and the upper circular plate turned it isevident that the threads of these parts will not mesh or engage again,the minutes-screw remaining fixed, unless gear.

the movement of the upper circular plate has been one or more wholedegrees and that the needle or Vernier will tell the number of thosedegrees. This is the basic principle of the whole device.

The operation is here explained by a single instance-namely, required,the angle between two objects. Having adjusted the instrument as inordinary cases, then, with the firstmentioned screw gear disengaged, thedial-screw tightened with its pointer at 60, and the sector-screwloosened, point the telescope at the first object and with the eccentricengage the threads of the first screw- Now if the glass does not stillpoint exactly at the object move it by turning the minutes-screw. Notethe course. If the needle is not exactly on a degree-mark, call thecourse, that which is indicated by the degreemark nearest the needle onthat side of it next to the north pole of the compass-box if the courseis northerly and the one next the south pole if the course is southerly.Read this way. We will say the course is N. 6 W. Pay no attention to theminutes. Now tighten the sector-screw, so as to rigidly fix theminutesscreW. Then with the eccentric disengage that screw-gear and movethe glass until it points at the second object. Now with the eccentric,assisted by gentle movements to and fro of the upper circular plate,with the hand engage the screw-gear. The movement now will have been acertain number of whole degrees. This engagement may have thrown theglass away from the object; but if what is thus directed has beencarefully done the glass will point within less than one degree towardthe second object; but it may be more than that. In either case nextloosen the sector-screw and the dial-screw and with the minutes-screwturn the glass to the second object, which may require one or morerevolutions of that screw. Now note the course, as before, by taking thedegree-mark nearest the needle, but on the same side of it as at thefirst time. Read in this way: the course is (we will say) N. 36 W. andthe minutesdial shows a further movement of (we will say) twentyminutes, which is to be added. If the pointer is between twominuteslines and the seconds are required, turn the minutes-screw backuntil the pointer coincides with the next minutes-line. Then with theseconds-pointer at 60 of the secondsdial fasten the sector-screw andwith the seconds-screw move the glass until it sights the second object,the seconds-dial indicating (We will say) thirty seconds. Then thereading will be from the compass-box, N.36 W. from the minutesdial,twenty'minutes, and from the seconds-dial thirty seconds. Deducting thefirst course, six degrees, we have the exact movement, 30", 20', 30",which is the required angle. This measurement may be made in this Way ina very expeditious manner inside of five minutes.

For convenience in readingit will be found preferable to use theinstrument with the north pole of the compass-box toward the north andto read the course in the manner above indicated. It will also be foundmore convenient if, in making the second engagement of the screw-gear,as above, the circular-plate be so moved that the glass will be turned alittle toward the first object, rather than beyond the second object.

This device is designed to be usually useful in triangulation and in allcases where the accurate measurement of an angle is required. As anattachment to an instrument for'measuring angles it is designed toprovide such means as will enable the operator to readily move thetelescope any number of whole degress and by positive means to measureand indicate accurately the minutes of such movement beyond the wholedegrees by one turn of a thumb-screw and by positive means to measureand indicate accurately the seconds of the movement beyond the minutesby one turn of another thumb-screw, the accuracy of the movement notbeing afiected by any variation or declination of the magnetic needle.

The means of positive measurement and indication of the minutes andseconds herein described are designed to be distinguished from suchmeans as involve the reading of an adjusted Vernier in its relation to agraduated dial-plate, such means of reading being subject to the nervouspersonality of the operator, and'therefore not mechanically positive,such as they are in the present invention, wherein the means which bringthe dialplates and indicators to their respective positions of exactmeasurement and indication are of mechanical character.

Having described my invention, what I claim, and desire to secure .byLetters Patent,

1. In an instrument for measuring angles,

the combination with the degree-plate, of the.

tangent minute-screw, its adjustable dial, the

set-screw for said dial, and the indicator, subfor such dial-plates, andmeans of engagement and disengagement between the minutes-screw and theseconds-screw, substantially as specified.

4. In an instrument for measuring angles, the combination with thedegree-plate, of a tangent minute-screw having degree pitch, itsdial-plate and indicator, and a secondsscrew having minute pitch, meansof engagement between the minute-screw and the seconds-screw, and meansof engagement between the minutescrew and said degreeplate,substantially as specified.

5. In an instrument for measuring angles, the combination with thecompass degreeplate, of a radially-adj ustable tangential minute-screw,and a seconds-screw, and means for detachably engaging said minute-screwand seconds-screw, substantially as specified.

6. In an instrument for measuring angles, the combination with thetelescope, of means for moving thetelescope any number of whole degrees,normally disconnected means of positive and even motion for measuringand indicating the minutes of the angle beyond the whole degrees, andnormally disconnected means of positive and even movement of measuringand indicating the seconds of the angle beyond the minutes,substantially as specified.

7. In an instrument for measuring angles, the combination with thetelescope, of means for moving the telescope and measuring andindicatingthe whole degrees of such movement, normally disconnectedmeans for measuring and indicating the minutes of such movement beyondsuch whole degrees, and normally disconnected means for measuring andindicating the seconds of such movement beyond such whole degrees andminutes, substantially as specified.

8. In an instrument for measuring angles,

the combination with the telescope, the de- HERBERT O. EMERY,

N. G. MCCARTHY.

